The requirements placed on image-forming apparatuses for higher color image quality have been increasing in recent years. In an image-forming apparatus such as a digital full-color copier or printer, the original image is first subjected to color separation by individual blue, green, and red filters. An electrostatic latent image corresponding to the original image is formed on the photosensitive member and is developed using individual colored developers, i.e., yellow, magenta, cyan, and black. As a consequence, the tinting strength exhibited by the colorant in each colored developer exercises a strong influence on image quality.
Specifically, in order to raise image quality there is desire in the printing industry to approximate the AdobeRGB that is used in the RGB workflow and to reproduce Japan Color.
However, at the present time additional improvements to the colorants are still necessary in order to reproduce the image quality of Japan Color or AdobeRGB.
Particularly with regard to the cyan colorant within this context, it has been said that the color space cannot be satisfactorily broadened with the copper phthalocyanine compounds in widespread use at the present time and that novel colorants must be developed (Japanese Patent Application Laid-open No. 2009-122496).
In order to solve this problem, a cyan colorant was developed that contains a phthalocyanine compound having a substituent on the central metal atom and an electrostatically developable toner having a high lightness and an excellent color tone was obtained when this cyan colorant was used (Japanese Patent Application Laid-open No. 2009-122496).